How Does Thermal Transfer Ribbon Work?

Thermal transfer printing is a fast and clean process with no warm-up or cooling time required. It is not a wet or dirty process either and the results are instantly dry, requiring no curing. By using a single-pass ribbon, the print is perfect from the start to the very end of a roll, making it the standard for producing barcodes and variable information labels, on-demand.

A thermal transfer label printer from the likes of Avery, Sato, TEC, Zebra etc produces text, barcodes and graphics by using a fixed low-powered print head which spans the entire width of the print area. The print head comprises of a single row of thousands of tiny elements (“dots”) of a size typically 8 or 12 dots per millimetre, yielding a print resolution of 200dpi or 300dpi – but even 600dpi is available.

The Difference Between “Direct Thermal” and “Thermal Transfer”:

A Direct Thermal printer uses the heat from the dots in the print head to activate a chemical coating in a specially produced thermal label, which darkens the area in contact with each dot, in order to produce the label image.  A Thermal Transfer printer uses a thermal ribbon:-

Thermal transfer ribbon is a roll of clear plastic (PE) film coated on one side with a coloured pigment, or “ink”, most commonly black (although many colours are available). Depending on the printing requirements, the coating can be formulated using either wax, resin or a mixture of both. The thermal transfer ribbon passes over the thermal print head, with the coated side pressed against the label surface. The heat energy produced by each dot causes the pigment to transfer off the carrier film and bond to the surface of the label.

The element dots which make up the print head are electronically heated up and cooled rapidly by the printer as both the label and ribbon pass under it at the same time. Speeds of 300mm per second and faster are quite achievable with the right match of ribbon, label and printer.

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